This invention relates to an endfire-type phased array antenna, and more particularly to an improved endfire-type phased array antenna having a high directivity in a wide frequency range and a high directivity protection.
In receiving of a television or FM broadcast, usually there is a problem of multi-path interference, so-called ghosts resulting from an echo of a reflected wave, and in order to prevent such ghosts various attempts have been carried out up to the present. For example, various ghost eliminating circuits using a delay line have been studied, but conventionally there is not provided a satisfactory system for preventing ghosts.
According to the experiments of the inventors, it is found that the most effective result for eliminating ghosts is provided by making the directivity of the antenna sharp and the directivity protection thereof high.
Although there is provided in the prior art an endfire-type phased array antenna having a sharp directivity, in conventional ones the high directivity is realized only around a designed frequency and it is used only in a very narrow band, as described hereinafter.